I have a 2004 F150 FX4 Supercab, I'm wanting to replace the exhaust on it. I am considering just replacing the stock muffler with a magnaflow s.s. muffler, or a flowmaster super 40. What is your opinion. Also is the magnaflow cat-back system worth the money over just replacing the muffler.

 

just replace the stock muffler with a Magnaflow SS muffler and a 4" tip. keep your stock piping. this is what i did

 

Thanks man, what size muffler did you use?

 

I replaced just the muffler with a Flowmaster 40 series 2-pass, was alittle loud in the cab at first, but after about 200 miles, has really mellowed out, and sounds great. Not too loud, not to quiet.
Total cost $ 150.00.
I did not get the chrome exhaust tip.

04 F150 XLT SUPER CAB 4.6

 

Magnaflow=mellow...some say too quiet.

Flowmaster=louder...some say too loud.

I say...go Magnaflow. Their rockwool, straigh-throughs grow on ya, get slightly louder over time, don't wake the neighbors at 5:00 A.M.

 

What size magnaflow ss muffler would I need?

inlet/outlet ?
case size?

 

If you go with the Magnaflow, should you expect any increase in performance or mileage, similar to the FlowMaster cat back system?

 

My experience with Magnaflow is related to the install on my previous '97 5.4 2V...a dual rear exit system. I'm awaiting the release of the same system for my '04. As to size, I only noted that the dealer will either (1) install a Magnaflow to 'fill' the OEM space or (2) after a discussion with you, size the Magnaflow to your preference: shorter=louder, longer=quieter. In this case, it's sort of "pay your money, take your chances" unless there is a vehicle on the lot to listen to.

One other thing I noted...a pile of brand-new, other brand, aftermarket mufflers in the corner that were pulled off vehicles because they were too loud according to the owners. They all appeared rather short to me, say 18-20 inches long.

Another thing about Magnaflows...you'll never get complaints from the wife or other passengers because of a 'booming' sound in the cab.

 

i opted for Magnaflow SS muffler # 14576. awesome sound and seemed to keep my low end and gain some top end. i say stay away from Flowmaster.

 

I had the same questions. So I asked the guys who install and sell the systems. Guess what opinions are like a--holes, everyone has one. Mike Troyer loves Magnaflow; Summit Racing recommends Flowmaster; local speed shop suggests Borla if you have the extra (it really isn't that much more); a 4 wheel drive shop suggests the Gibson. But my problem still exists because no one was able to give me actual evidence of improvement in HP, torque, or mpg; just "seat of the pants" knowledge which takes me back to opinions are like...So I guess we should go by looks and sound...now I just have to find someone around my way who has installed one of the above exhaust systems.

 

Magnaflow, Borla, Gibson, Dynomax with Flowmaster trailing behind.

 

Thanks for the help, Im going to go ahead and go with the Magnaflow ss #14246. This is the one that is included with their cat-back system.

 

Any opinions on the si/do magnaflows? I guess I should clarify. opinions about performance losses or gains and sounds?

thanks, tj

 

You may want to check out this site. They have pics and sound.

I am thinking of a Borla true dual system for my 04 FX4. I stopped at a local muffler shop that specializes in custom exhaust. here is a link for anyone interested. If you click on custom exhaust they have pics of systems they have installed.

www.mightymuffler.net

 

What is the product number for the magnaflow (not ss) for the '04 Screw